Checking your PBX's incoming numbers
Why you need it#
A phone number at your provider can stop taking calls: the account ran out of money, the provider blocked the number or disconnected it. The worst part is that from the PBX side everything looks fine: the trunk is registered, the provider answers the connection check — and guests' calls simply never reach you. Usually you learn about it from the guests themselves, a day or two later, after some orders and bookings are already lost.
The incoming number check catches exactly this case and tells you as soon as a number stops taking calls.
How it works#
- On a schedule the PBX dials your number through another trunk of the same location (for example, the "Mango" number through the "Beeline" trunk) and waits for the call to come back to it on that number.
- The call arrived — the number takes calls. It did not — in 3 minutes the PBX checks again, through another trunk if possible. Two failures in a row — the number is marked "Does not receive calls" and you get a message.
- Any real incoming call to the number is proof too: the scheduled check is not needed this time, and the PBX skips it.
- If the location has several trunks, a number is checked through two at once (up to four — a location setting): any call that gets through means the number takes calls, and the rest are cancelled right away. A trunk that refused the call is replaced by the next one immediately.
Checking a number's outgoing calls#
Once a day, during the location's working hours, the PBX checks the opposite too — whether the number calls out: it dials your own numbers on other trunks from it. Any call that gets through means outgoing works. A real successful outgoing conversation from this number during the day replaces the check call, and an incoming check that came in from the number confirms its outgoing calls as well.
- "Not calling out: the trunk does not allow outgoing calls (SIP 403)" — the provider does not allow outgoing calls for this account, or does not allow this caller ID: check the outgoing-call permissions in the provider's account.
- Is the number only needed for incoming calls? Mark it "incoming only" — then outgoing is not checked.
- An "outgoing only" trunk (incoming calls turned off) is checked for outgoing. If a trunk has only "for checking" (reference) numbers, its outgoing is checked through one of them — for the others the table says "the trunk's outgoing is checked by number …". If the trunk does not allow outgoing calls, the number is "not calling out" and you get a push, just as for an ordinary number.
- Checking outgoing needs a number on another trunk — otherwise "nowhere to call: there is no other trunk with a number".
The checking trunk refuses#
If the provider of the checking trunk answers the call with a refusal 401, 402, 403, 407 or 603 — it does not allow outgoing calls from this trunk or with this caller ID — that says nothing about your number. The number gets the mark "not checked", the trunk gets a "Does not allow outgoing calls (SIP 403)" badge, and for 6 hours (or until the first successful check through it) it is not used as a checking trunk. In the number window pick another trunk to check with, or "Automatically". If a false "not taking calls" alarm came earlier because of such a refusal, you get one correction message, "The 'not taking calls' alarm was false…". "Not taking calls" is set only if at least one trunk honestly reached the network but the call did not come to us; if all checking trunks refused, the number is simply "not checked".
Does it cost anything#
Nobody picks up: the PBX sees the incoming call, keeps it in the "ringing" state and cancels its own outgoing call. There is no conversation, so providers normally do not bill such a call. It does not ring your staff and does not show up in missed calls, callbacks, reports, recordings or paid minutes.
To avoid bothering the provider with frequent short calls, by default a number is checked once every 3 hours during the location's working hours and no more than 12 times a day. If your provider charges even for unanswered calls, lower the frequency or turn the check off for that number.
Customers' calls count too. Every real customer call that reaches the PBX on a number (even an unanswered one) proves that incoming works, and a successful outgoing conversation from the number proves that outgoing works. While such calls keep coming, the scheduled check of the number does not go out: the "Number check" row shows "confirmed by live calls: 14 in 24 hours, last at 12:55", and the hint says "scheduled check skipped — customer calls were coming in". After a restart the PBX remembers the calls of the last 24 hours and does not immediately start checking numbers that have just been taking customers' calls.
Sound check (paid calls)#
The ordinary check only looks at whether a call gets through. If you need to know that the call that got through has sound, turn on the "Sound check (paid calls)" section in the "How to check the location's numbers" window — it is off by default.
- This is a real connection of 10–20 seconds: the PBX calls its own number through another trunk, answers that call itself (only if it recognised its own number as the caller — a live customer on the number will not get a call answered by the PBX) and plays test tones in both directions in turn.
- The result is "good / acceptable / poor", "no sound reaches the caller" or "the caller cannot be heard", plus delay, loss, jitter and the MOS quality score for each direction.
- The provider bills such connections. The form shows how many connections per month you get at the chosen frequency (from 4 times a day to once a week). The "Check sound now" button in the number window — no more than 3 times an hour.
- "No sound" in one of the directions turns the "Number check" row red and arrives as a push: "the call goes through, but no sound reaches the caller".
When the check is on#
By default the check turns on by itself for a number that has something to check it with: the location has another enabled trunk, and from the same country. A number on the only trunk is not checked by default — the number window will suggest "add a second trunk or allow checking through the same trunk".
- Your "Off" for a number is never overridden — but "Check now" still works.
- A new number is checked right after it is added — this also catches a typo in the number.
- Not checked: numbers that arrive by forwarding, through a gateway or as a web call, disabled numbers, and numbers of a trunk whose incoming calls are turned off.
Where it is in the panel#
- Telephony → Phone providers. Under a trunk row are its numbers with a coloured status dot. If a number is not taking calls, a "Not receiving calls: N" badge appears next to the trunk, and a banner with the reason and advice appears above the list.
- "＋ number" in the trunk menu adds a number the provider attached to this trunk. After saving, the PBX checks it right away.
- Click a number (or "Number check" in the number menu on the "Lines" tab) to open the "Number check"
window:
- "Check that calls to this number get through": Auto / On / Off — with an explanation of why it is so right now;
- "Check with": automatically — any other trunk of the location, or only the selected trunks, in this order;
- "Check through the same trunk when there is no other";
- "Check now" with a choice of trunk — the result usually arrives in about half a minute;
- check history: when, through which trunk, the reason, the result and how many seconds the call took.
- "Configure" above the number list opens the common check rules for all numbers of the location. The "Number check" row next to it shows the overall status as a circle — "All good", "Needs attention" or "Failure" — the time of the last check and a "why" hint for numbers and directions. A grey circle "Not checked yet" means there are numbers under watch but none has a result yet.
- Telephony → Setup → Lines → "Location numbers: incoming and outgoing" — all trunk numbers with "Incoming" and "Outgoing" columns: the state, what and when confirmed it, and the buttons "Check incoming", "Check outgoing" and "Check all" (next to them — how many checks are left this hour). While the block is open, the progress of a check is visible live: "from → to" and the stage — dialling, ringing, announcement, "got through ✓", "refused 403 — the trunk does not allow outgoing calls", "cancelled — another leg got through". The line "PBX online — live progress of checks" says that the live channel is open.
Location settings#
The "How to check the location’s numbers" window. Recommended values are marked; "Restore recommended" resets everything.
| Setting | Recommended | Limits |
|---|---|---|
| How often to check | every 3 h | from 30 min to 24 h |
| When | during the location's working hours + 30 min before opening | around the clock / your own hours and days |
| Allow the same trunk if there is no other | yes (a weaker check) | — |
| Allow a trunk of another country | no (the call may cost like an international one) | — |
| Max checks of one number per day | 12 | from 1 to 48 |
| Consider the number not taking calls after failures in a row | 2 | from 1 to 3 |
| Who to notify | the owner, telephony administrators, email to the owner, on recovery | — |
Manual "Check now" checks are limited to 10 per hour per location; scheduled checks keep running as usual.
States and check results#
| Number state | What it means |
|---|---|
| 🟢 Receives calls | the last check got through, or there was a real incoming call |
| 🟡 Suspicious | one check did not get through; the PBX is re-checking |
| 🔴 Does not receive calls | failures in a row; the mark clears itself after the first successful check |
| ⚪ No data yet | there have been no checks yet, or the PBX has not reported for a long time |
| ◯ Not checked | the check is off or there is nothing to check with |
Results in the history: "got through" · "got through, but on another trunk" (the number lands in the wrong place) · "did not get through" · "provider: number does not exist" · "callers hear a provider message" · "calls go to the provider's voicemail" · "checking trunk 'X' refused the outgoing call (SIP 403) — number not checked" · "skipped" (nothing to check with, the trunk is busy with calls, the daily limit is used up). A failure of the checking trunk never marks your number as not taking calls.
Who finds out and how#
When a number stops taking calls, the owner and staff with the "Telephony" permission at the "Edit" level for this location get a push on their phone (Cenaly Business and Cenaly Phone) and a notification in Cenaly Business for Windows, plus a message in the work chat; the owner also gets an email:
When the number takes calls again, you get a "taking calls again" message with the downtime. There is at most one "down" and one "recovered" message per number every 6 hours. The "Check connection" button in the telephony overview shows an "Incoming numbers" link as well.
Other line failures also arrive as a push — one message per failure, not per number: "Incoming calls are not getting through: trunk 'Mango', numbers … (+6)", "Trunk '…' has been out of touch with the provider since 12:20", "… rejects outgoing calls (SIP 403)", "PBX unavailable since 12:31". An alarm is confirmed after 10 minutes and arrives only about something that used to work; when it is fixed — "getting through again … (downtime ~2 h)". Tapping the push opens the right window in "Telephony".
What to do if a number is not taking calls#
- Open the account of this number's provider (the number's own trunk, not the checking one) and check the balance and the number's status — the most common cause.
- "Provider: number does not exist" — the number may have been disconnected, or there is a typo in the number.
- "Calls go to the provider's voicemail" — the provider has its own forwarding turned on: turn it off in the provider's account.
- After the fix, press "Check now" in the number window. If it succeeds, the mark clears and you get a recovery message.
Limitations#
- Works only on the location's dedicated PBX with outgoing calls enabled: provider trunks exist only there. On the shared server, on your own PBX through the PC bridge and on old firmware the check is unavailable — the number window says so.
- You need a second trunk: checking through the same trunk is weaker (the provider may loop the call inside its own network), and we cannot call your number from a platform number.
- The ordinary check proves the call reaches the PBX. Sound in the call is checked only by the paid "Sound check" (off by default).
- If the provider replaces or hides the checking call's number, the check cannot be told apart from a guest's call: such a call is held for about 3 seconds and counted, and after two such cases in a row automatic checks of the number are paused with an explanation.
- When a number is not taking calls the PBX only notifies you: the outgoing caller ID and the numbers in your ads are not switched automatically.
- The "during working hours" mode takes the working hours and holidays from the location card. The PBX learns new hours when someone opens the Telephony section or changes the PBX settings. If the location has no working hours filled in, checks run around the clock except 23:00–07:00, and there is no check 30 minutes before opening.
FAQ#
The trunk is green but the number "does not receive calls" — is that a mistake?#
No. A green trunk only means the PBX is connected to the provider. With an unpaid balance the provider often keeps the registration but stops delivering calls to the number — exactly what the check catches.
Why is the check off for a number when I did not turn it off?#
There is nothing to check it with: the location has no other enabled trunk from the same country. Add a second trunk or allow checking through the same trunk — in the number window or in the location settings.
Will my staff hear the check call?#
No. The check call does not reach staff, the missed-call list or the reports.